Patent Document 1 describes an example of a known vehicle seat sliding device. Such a vehicle seat sliding device includes lower rails and upper rails, and the upper rails are coupled with the lower rails in a movable manner. A plastic cover is mounted on the upper rail, which is formed by a plate, such that the cover closes a first end located at one end of the upper rail. Direct interference between the first end and surrounding parts may be avoided by reducing exposure of the first end of the upper rail in this manner.